In a typical ink jet recording or printing system, ink droplets are ejected from a nozzle at high speed towards a recording element or medium to produce an image on the medium. The ink droplets, or recording liquid, generally comprise a recording agent, such as a dye or pigment, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water, an organic material such as a monohydric alcohol, a polyhydric alcohol or mixtures thereof.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-forming layer, and includes those intended for reflection viewing, which have an opaque support, and those intended for viewing by transmitted light, which have a transparent support.
While a wide variety of different types of image-recording elements for use with ink jet devices have been proposed heretofore, there are many unsolved problems in the art and many deficiencies in the known products which have severely limited their commercial usefulness. The requirements for an image recording medium or element for ink jet recording are very demanding.
It is well known that in order to achieve and maintain photographic-quality images on such an image-recording element, an ink jet recording element must:
Be readily wetted so there is no puddling, i.e., coalescence of adjacent ink dots, which leads to nonuniform density PA1 Exhibit no image bleeding PA1 Exhibit the ability to absorb high concentrations of ink and dry quickly to avoid elements blocking together when stacked against subsequent prints or other surfaces PA1 Provide a high level of gloss and avoid differential gloss PA1 Exhibit no discontinuities or defects due to interactions between the support and/or layer(s), such as cracking, repellencies, comb lines and the like PA1 Not allow unabsorbed dyes to aggregate at the free surface causing dye crystallization, which results in bloom or bronzing effects in the imaged areas PA1 Have an optimized image fastness to avoid fade from contact with water or radiation by daylight, tungsten light, or fluorescent light PA1 B represents units of a copolymerizable, .alpha.,.beta.-ethylenically unsaturated monomer; PA1 Q is N or P; PA1 R.sub.1, R.sub.2 and R.sub.3 each independently represents a carbocyclic or alkyl group; PA1 M.sup.- is an anion; PA1 x is from about 0.25 to about 5 mole percent, preferably 1.0 to 5.0 mole percent; PA1 y is from about 0 to about 90 mole percent, preferably 0 to 45 mole percent; and PA1 z is from about 10 to about 99 mole percent, preferably 40 to 90 mole percent. PA1 X represent halide anion; and PA1 y is 1 to about 30.
It has been observed that in certain ink jet image recording elements, the imaged or "inked" areas will experience a color or hue shift when exposed to high humidity and/or slow drying conditions. This hue shift is also dependent upon the specific ink sets from different manufacturers. The cause of this hue shift is a result of the dyes having sufficient moisture in the ink-receiving layer of the media to allow the dyes to continue to migrate or spread with time in the ink-receiving layer. An image that is exposed to high humidity or very slow drying conditions, or covered after being printed thus slowing drying, will experience a hue or color shift over time.